CN210720791U

CN210720791U - Negative optical power electrowetting optical device, camera module, liquid shutter and negative optical power liquid system

Info

Publication number: CN210720791U
Application number: CN201920735068.2U
Authority: CN
Inventors: 约瑟夫·马歇尔·库尼克; 肖恩·迈克尔·奥马利
Original assignee: Corning Inc
Current assignee: Corning Inc
Priority date: 2018-05-21
Filing date: 2019-05-21
Publication date: 2020-06-09
Anticipated expiration: 2029-05-21
Also published as: TW202004225A; CN110515147A; WO2019226483A1; US20210223442A1

Abstract

A negative optical power electrowetting optical device is provided. The negative optical power electrowetting optical device comprises: a non-conductive liquid having a refractive index; a conductive liquid having a second refractive index; and a dielectric surface in contact with both the conductive liquid and the non-conductive liquid. The non-conductive liquid has a refractive index less than the second refractive index of the conductive liquid, and wherein the conductive liquid is immiscible with the non-conductive liquid.

Description

Negative optical power electrowetting optical device, camera module, liquid shutter and negative optical power liquid system

Cross Reference to Related Applications

This application claims priority to U.S. provisional application No.62/674,511, filed on 21/5/2018, the contents of which are incorporated herein by reference in their entirety.

Technical Field

The present disclosure relates to liquid lenses, and more particularly, to liquid lenses having negative optical power using a low refractive index hydrophobic liquid.

Background

Conventional liquid lenses based on electrowetting are based on two immiscible liquids, namely an oil and a conductive phase, which are water-based, arranged in a chamber. The two liquid phases typically form a triple interface on an isolated substrate comprising a dielectric material. Varying the electric field applied to the liquids can change the wettability of one of the liquids with respect to the chamber wall, which has the effect of changing the shape of the meniscus formed between the two liquids. Furthermore, in various applications, a change in meniscus shape results in a change in the focal length of the lens.

As liquid lenses expand into new and expanding application areas, it may be beneficial for the liquid formulations used in these devices to be able to respond rapidly to voltage under a variety of different environmental conditions to provide, for example, auto-focus and optical image stabilization functions. One of the disadvantages of using known liquid formulations, especially oil phases, is the high dispersion or variation of the refractive index over a range of wavelengths. The search for oils with desirable refractive indices and low dispersion enables new and/or improved liquid lens applications.

Accordingly, there is a need for liquids used in liquid lens configurations that provide reduced chromatic aberration for a desired refractive index, which can translate into improved liquid lens reliability, performance, and manufacturing costs.

SUMMERY OF THE UTILITY MODEL

According to some embodiments of the present disclosure, a negative optical power electrowetting optical device is provided. The negative optical power electrowetting optical device comprises: a non-conductive liquid having a refractive index; a conductive liquid having a second refractive index; and a dielectric surface in contact with both the conductive liquid and the non-conductive liquid. The non-conductive liquid has a refractive index less than the second refractive index of the conductive liquid, and wherein the conductive liquid is immiscible with the non-conductive liquid.

According to some embodiments of the present disclosure, a liquid shutter is provided. The liquid shutter includes a negative optical power electrowetting optical device having: a non-conductive liquid having a refractive index; a conductive liquid having a second refractive index; and a dielectric surface in contact with both the conductive liquid and the non-conductive liquid. The liquid shutter further includes: an imaging lens; and a blocking member located between the negative optical power electrowetting optical device and the imaging lens. The non-conductive liquid has a refractive index less than the second refractive index of the conductive liquid, and wherein the conductive liquid is immiscible with the non-conductive liquid.

According to some embodiments of the present disclosure, a negative optical power liquid system is provided. The negative optical power liquid system includes a non-conductive liquid having a refractive index and a conductive liquid having a second refractive index. The non-conductive liquid has a refractive index less than the second refractive index of the conductive liquid, and wherein the conductive liquid is immiscible with the non-conductive liquid.

Additional features and advantages will be set forth in the detailed description which follows, and in part will be readily apparent to those skilled in the art from that description or recognized by practicing the embodiments as described herein, including the detailed description which follows, the claims, as well as the appended drawings.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and are intended to provide an overview or framework for understanding the nature and character of the disclosure and the appended claims.

The accompanying drawings are included to provide a further understanding of the principles of the disclosure, and are incorporated in and constitute a part of this specification. The drawings illustrate one or more embodiments and, together with the description, serve to explain, by way of example, the principles and operations of the disclosure. It should be understood that the various features of the present disclosure disclosed in the specification and the drawings may be used in any and all combinations. As a non-limiting example, various features of the present disclosure may be combined with one another according to the following embodiments.

Drawings

The following is a description of the various figures in the drawings. The figures are not necessarily to scale and certain features and certain views of the figures may be shown exaggerated in scale or in schematic in the interest of clarity and conciseness.

In the drawings:

fig. 1 is a schematic cross-sectional view of an exemplary electrowetting optical device according to some embodiments of the present disclosure.

Fig. 2 is a schematic cross-sectional view of a conventional liquid lens providing positive optical power.

Fig. 3 is a schematic cross-sectional view of a liquid lens providing a sloped interface according to some embodiments of the present disclosure.

Fig. 4 is a schematic cross-sectional view of a liquid lens providing negative optical power according to some embodiments of the present disclosure.

Fig. 5 is a graph of chromatic aberration for positive and negative optical power liquid lenses according to some embodiments of the present disclosure.

Fig. 6A-6C are schematic cross-sectional views of a liquid shutter according to some embodiments of the present disclosure.

Fig. 7A-7B are schematic cross-sectional views of a liquid lens positioned with optics in a cell phone camera module according to some embodiments of the present disclosure.

Detailed Description

Additional features and advantages will be set forth in the detailed description which follows, and in part will be readily apparent to those skilled in the art from that description or recognized by practicing the embodiments as described below, together with the claims and appended drawings.

As used herein, the term "and/or," when used in a list of two or more items, means that any one of the listed items can be used alone, or any combination of two or more of the listed items can be used. For example, if a composition is described as comprising components A, B and/or C, the composition may comprise a only; only B is contained; only C is contained; a combination comprising A and B; a combination comprising A and C; a combination comprising B and C; or a combination comprising A, B and C.

In this document, relational terms such as first and second, top and bottom, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions.

Modifications of the disclosure will occur to those skilled in the art and to those who make or use the disclosure. Therefore, it is to be understood that the embodiments shown in the drawings and described above are merely for illustrative purposes and are not intended to limit the scope of the present disclosure, which is defined by the following claims as interpreted according to the principles of patent law, including the doctrine of equivalents.

For the purposes of this disclosure, the term "coupled" (in all its forms) generally means that two components are connected to each other either directly or indirectly. Such a connection may be fixed in nature or may be movable in nature. Such joining may be achieved through the two components and any additional intermediate members, and any additional intermediate members may be integrally formed as a single unitary body with each other or with the two components. Unless otherwise specified, such attachment may be permanent in nature, or may be removable or releasable in nature.

As used herein, the term "about" means that amounts, sizes, formulations, parameters, and other quantities and characteristics are not and need not be exact, but may be approximate and/or larger or smaller as desired, reflecting tolerances, conversion factors, rounding off, measurement error and the like, and other factors known to those of skill in the art. When the term "about" is used to describe a value or an end-point of a range, the disclosure should be understood to include the specific value or end-point referred to. Whether or not the numerical value or the end point of the range in the specification recites "about," the end point of the numerical value or the range is intended to include two embodiments: one modified by "about" and one not modified by "about". It will be further understood that the endpoints of each of the ranges are significant both in relation to the other endpoint, and independently of the other endpoint.

The term "substantially" and variations thereof as used herein is intended to indicate that the feature being described is equal or approximately equal to a value or description. For example, a "substantially planar" surface is intended to mean a planar or near-planar surface. Further, "substantially" is intended to mean that two values are equal or approximately equal. In some embodiments, "substantially" may mean values within about 10% of each other, such as within about 5% of each other, or within about 2% of each other.

Directional terms used herein, such as upper, lower, right, left, front, rear, top, bottom, are used with reference to the drawings as drawn, and are not intended to imply absolute orientations.

As used herein, the terms "the", "a", or "an" mean "at least one" and should not be limited to "only one" unless explicitly indicated to the contrary. Thus, for example, reference to "a component" includes embodiments having two or more such components, unless the context clearly indicates otherwise.

The terms "immiscible" and "immiscible" refer to liquids that do not form a homogeneous mixture when added together or that minimally mix when one liquid is added to another liquid. In this specification and in the following claims, two liquids are considered immiscible when their partial miscibility is below 2%, below 1%, below 0.5%, or below 0.2%, all values being measured within a given temperature range (e.g. at 20 ℃). The liquids herein have low mutual miscibility over a wide temperature range (e.g., including-30 ℃ to 85 ℃ and from-20 ℃ to 65 ℃).

As used herein, the term "conductive liquid" refers to a liquid having a conductivity of about 1 x 10^-3S/m to about 1X 10²S/m, from about 0.1S/m to about 10S/m, or from about 0.1S/m to about 1S/m. As used herein, the term "non-conductive liquid" refers to a liquid having little or no measurable conductivity, including, for example, less than about 1 x 10^-8S/m, less than about 1X 10^-10S/m, or less than about 1X 10^-14Conductivity of S/m.

Unless otherwise stated, the refractive index values reported herein are reported as measured at a wavelength of 589 nm.

In various embodiments, a negative optical power electrowetting optical device is provided. The negative optical power electrowetting optical device includes a non-conductive liquid having a refractive index; a conductive liquid having a second refractive index; and a dielectric surface in contact with both the conductive liquid and the non-conductive liquid. The non-conductive liquid has a refractive index less than the second refractive index of the conductive liquid, and wherein the conductive liquid is immiscible with the non-conductive liquid.

The "non-conductive liquid" described herein may be a low refractive index, low dispersion, non-polar, non-conductive liquid for use as an active element in a liquid electrowetting optical device having negative optical power. Such low index, low dispersion, non-polar, non-conductive liquids are used herein in place of the high index, high dispersion liquids typically used in positive optical power liquid lenses, instead of forming negative liquid lenses. The use of the negative optical power liquid lenses or negative optical power electrowetting optics described herein is important because they have no mechanical parts, but use electrowetting to actuate the lens as a focusing optic. These electrowetting devices use a two-liquid system, where one liquid is used as the light guiding element and a second liquid is used to support the light guiding element. The light-conducting liquid is typically an oil-based liquid, while the second liquid is an anti-freeze liquid, which is typically electrically conductive and polar. In conventional liquid lenses, in order to manufacture a positive lens, the oil has a higher refractive index than the polar liquid. By designing and selecting a non-conductive liquid with a refractive index lower than the refractive index of the respective conductive liquid, a negative optical power electrowetting device or a negative optical power liquid lens can be manufactured.

As described in more detail below, in fig. 1, the cell of the electrowetting optical device or liquid lens is typically defined by two transparent insulating plates and sidewalls. The lower plate is non-planar and includes conical or cylindrical recesses or grooves that contain a non-conductive or insulating liquid. The remainder of the cell is filled with a conductive liquid that is immiscible with the insulating liquid, has a different refractive index and substantially the same density. One or more drive electrodes are located on the sidewalls of the recess. A thin insulating layer may be introduced between the drive electrode and the respective liquid to provide electrowetting on the dielectric surface with long term chemical stability. The common electrode is in contact with the conductive liquid. By the electrowetting phenomenon, the curvature of the interface between the two liquids can be changed according to the voltage V applied between the electrodes. Thus, depending on the applied voltage, the light beam passing through the cell perpendicular to the plate in the droplet region will be defocused to a more or less different degree. The conductive liquid is typically an aqueous salt solution. The non-conducting liquid is typically an oil, an alkane, or a mixture of alkanes, possibly halogenated.

In some embodiments, the voltage difference between the voltage at the common electrode and the voltage at the drive electrode may be adjusted. The voltage difference can be controlled and adjusted to move the interface between the liquids (i.e. the meniscus) to a desired position along the side wall of the chamber. By moving the interface along the sidewalls of the cavity, the focus (e.g., diopter), tilt, astigmatism, and/or higher order aberrations of the liquid lens can be changed.

Liquid lens structure

Referring now to fig. 1, a simplified cross-sectional view of an exemplary liquid lens 100 is provided. The structure of the liquid lens 100 is not meant to be limiting and may include any structure known in the art. In some embodiments, the liquid lens 100 can include a lens body 102 and a cavity 104 formed in the lens body 102. A first liquid 106 and a second liquid 108 may be disposed within the cavity 104. In some embodiments, the first liquid 106 may be a polar liquid, also referred to as a conductive liquid. Additionally or alternatively, the second liquid 108 may be a non-polar liquid and/or an insulating liquid, also referred to as a non-conducting liquid. In some embodiments, the interface 110 between the first liquid 106 and the second liquid 108 forms a lens. For example, the first liquid 106 and the second liquid 108 may be immiscible in each other and have different refractive indices such that an interface 110 between the first liquid and the second liquid forms a lens. In some embodiments, the first liquid 106 and the second liquid 108 may have substantially the same density, which may help avoid changes in the shape of the interface 110 due to changing the physical orientation of the liquid lens 100 (e.g., due to the effects of gravity).

In some embodiments of the liquid lens 100 depicted in fig. 1, the cavity 104 may include a first portion (or headspace) 104A and a second portion (or base portion) 104B. For example, as described herein, the second portion 104B of the cavity 104 may be defined by an aperture in an intermediate layer of the liquid lens 100. Additionally or alternatively, as described herein, the first portion 104A of the cavity 104 may be defined by a groove in the first outer layer of the liquid lens 100 and/or disposed outside of a hole in the intermediate layer. In some embodiments, at least a portion of the first liquid 106 may be disposed in the first portion 104A of the cavity 104. Additionally or alternatively, the second liquid 108 may be disposed within the second portion 104B of the cavity 104. For example, substantially all or a portion of the second liquid 108 may be disposed within the second portion 104B of the chamber 104. In some embodiments, the perimeter of the interface 110 (e.g., the edge of the interface that contacts the sidewall of the cavity) may be disposed within the second portion 104B of the cavity 104.

The interface 110 of the liquid lens 100 (see fig. 1) may be adjusted via electrowetting. For example, a voltage may be applied between the first liquid 106 and a surface of the cavity 104 (e.g., one or more drive electrodes located near the surface of the cavity 104 and insulated from the first liquid 106 as described herein) to increase or decrease the wettability of the surface of the cavity 104 with respect to the first liquid 106 and to change the shape of the interface 110. In some embodiments, interface 110 is adjusted to change the shape of interface 110, which changes the focal length or focus of liquid lens 100. Such a change in focal length may, for example, enable liquid lens 100 to perform an autofocus function. Additionally or alternatively, the interface 110 is adjusted to tilt the interface relative to the optical axis 112 of the liquid lens 100. For example, such tilting may enable the liquid lens 100 to perform an Optical Image Stabilization (OIS) function in addition to providing astigmatism variation or higher order optical aberration correction. Adjustment interface 110 may be accomplished without requiring physical movement of liquid lens 100 relative to an image sensor, a stationary lens or lens stack, a housing, or other component of a camera module in which liquid lens 100 may be incorporated.

In some embodiments, the lens body 102 of the liquid lens 100 can include a first window 114 and a second window 116. In some such embodiments, the cavity 104 may be disposed between the first window 114 and the second window 116. In some embodiments, the lens body 102 may include multiple layers that collectively form the lens body. For example, in the embodiment shown in fig. 1, the lens body 102 may include a first outer layer 118, an intermediate layer 120, and a second outer layer 122. In some such embodiments, the intermediate layer 120 may include apertures formed therethrough. First outer layer 118 may be bonded to one side (e.g., the object side) of intermediate layer 120. For example, first outer layer 118 may be bonded to intermediate layer 120 at bond 134A. The joint 134A may be an adhesive joint, a laser joint (e.g., a laser weld), a mechanical closure, or any other suitable joint capable of retaining the first and

second liquids

106, 108 within the cavity 104. Additionally or alternatively, the second outer layer 122 may be bonded to another side (e.g., the imaging side) of the intermediate layer 120. For example, second outer layer 122 may be bonded to intermediate layer 120 at bond 134B and/or bond 134C, each of

bonds

134B and 134C may be configured as described herein with respect to bond 134A. In some embodiments, the middle layer 120 may be disposed between the first and second

outer layers

118, 122, opposing sides of the aperture in the middle layer may be covered by the first and second

outer layers

118, 122, and at least a portion of the cavity 104 may be defined within the aperture. Thus, a portion of the first outer layer 118 covering the cavity 104 may serve as the first window 114 and a portion of the second outer layer 122 covering the cavity may serve as the second window 116.

In some embodiments, the cavity 104 may include a first portion 104A and a second portion 104B. For example, in the embodiment shown in fig. 1, the second portion 104B of the cavity 104 may be defined by an aperture in the intermediate layer 120, and the first portion 104A of the cavity may be disposed between the second portion 104B of the cavity 104 and the first window 114. In some embodiments, the first outer layer 118 may include a recess as shown in fig. 1, and the first portion 104A of the cavity 104 may be disposed within the recess of the first outer layer 118. Thus, the first portion 104A of the cavity 104 may be disposed outside of the aperture in the intermediate layer 120.

In some embodiments, the cavity 104 (e.g., the second portion 104B of the cavity 104) may be tapered as shown in fig. 1 such that the cross-sectional area of the cavity 104 decreases along the optical axis 112 in a direction from the object side to the imaging side. For example, the second portion 104B of the cavity 104 may include a narrow end 105A and a wide end 105B. The terms "narrow" and "wide" are relative terms, meaning that the narrow end 105A is narrower than the wide end 105B. Such a tapered cavity may help maintain alignment of the interface 110 between the first liquid 106 and the second liquid 108 along the optical axis 112. In other embodiments, the cavity 104 is tapered such that the cross-sectional area of the cavity 104 increases along the optical axis in a direction from the object side to the imaging side, or is non-tapered such that the cross-sectional area of the cavity 104 remains substantially constant along the optical axis.

In some embodiments, image light may enter the liquid lens 100 depicted in fig. 1 through the first window 114, may be refracted at the interface 110 between the first liquid 106 and the second liquid 108, and may exit the liquid lens 100 through the second window 116. In some embodiments, the first outer layer 118 and/or the second outer layer 122 may include sufficient transparency to allow image light to pass through. For example, the first outer layer 118 and/or the second outer layer 122 may include a polymer, glass, ceramic, or glass-ceramic material. In some embodiments, the outer surface of the first outer layer 118 and/or the second outer layer 122 may be substantially flat. Thus, even though liquid lens 100 may function as a lens (e.g., by refracting image light through interface 110), the outer surface of liquid lens 100 may be flat, rather than curved like the outer surface of a fixed lens. In other embodiments, the outer surface of the first outer layer 118 and/or the second outer layer 122 may be curved (e.g., concave or convex). Thus, the liquid lens 100 may comprise an integrated stationary lens. In some embodiments, the intermediate layer 120 may comprise a metal, polymer, glass, ceramic, or glass-ceramic material. The intermediate layer 120 may be transparent or opaque, as the image light may pass through via the holes in the intermediate layer 120.

In some embodiments, the liquid lens 100 (see fig. 1) may include a common electrode 124 in electrical communication with the first liquid 106. Additionally or alternatively, the liquid lens 100 may include one or more drive electrodes 126 disposed on sidewalls of the cavity 104 and insulated from the first and

second liquids

106, 108. As described herein, different voltages may be provided to the common electrode 124 and the drive electrode 126 to change the shape of the interface 110.

In some embodiments, the liquid lens 100 (see fig. 1) may include a conductive layer 128, at least a portion of the conductive layer 128 being disposed within the cavity 104. For example, the conductive layer 128 may include a conductive coating applied to the intermediate layer 120 prior to bonding the first outer layer 118 and/or the second outer layer 122 to the intermediate layer. Conductive layer 128 may include a metallic material, a conductive polymer material, other suitable conductive material, or a combination thereof. Additionally or alternatively, the conductive layer 128 may comprise a single layer or multiple layers, some or all of which may be conductive. In some embodiments, the conductive layer 128 may define the common electrode 124 and/or the drive electrode 126. For example, the conductive layer 128 may be applied to substantially the entire outer surface of the intermediate layer 120 prior to bonding the first outer layer 118 and/or the second outer layer 122 to the intermediate layer. After applying the conductive layer 128 to the intermediate layer 120, the conductive layer may be divided into various conductive elements (e.g., the common electrode 124 and/or the drive electrode 126). In some implementations, the liquid lens 100 can include scribe lines 130A in the conductive layer 128 to isolate (e.g., electrically isolate) the common electrode 124 and the drive electrode 126 from each other. In some embodiments, scribe line 130A may comprise a gap in conductive layer 128. For example, the scribe line 130A is a gap having a width of about 5 μm, about 10 μm, about 15 μm, about 20 μm, about 25 μm, about 30 μm, about 35 μm, about 40 μm, about 45 μm, about 50 μm, or any range defined by the listed values.

As also shown in fig. 1, the liquid lens 100 may include an insulating element 132 disposed within the cavity 104 on top of the drive electrode layer. For example, the insulating element 132 may include an insulating coating applied to the intermediate layer 120 prior to bonding the first outer layer 118 and/or the second outer layer 122 to the intermediate layer. In some embodiments, the insulating element 132 may include an insulating coating applied to the conductive layer 128 and the second window 116 after bonding the second outer layer 122 to the intermediate layer 120 and before bonding the first outer layer 118 to the intermediate layer. Accordingly, the insulating element 132 may cover at least a portion of the conductive layer 128 and the second window 116 within the cavity 104. In some embodiments, the insulating element 132 may be sufficiently transparent to enable image light to pass through the second window 116, as described herein.

In some embodiments of the liquid lens 100 depicted in fig. 1, the insulating element 132 may cover at least a portion of the drive electrodes 126 (e.g., the portion of the drive electrodes disposed within the cavity 104) to insulate the first and

second liquids

106, 108 from the drive electrodes. Additionally or alternatively, at least a portion of the common electrode 124 disposed within the cavity 104 may be uncovered by the insulating element 132. Thus, as described herein, the common electrode 124 may be in electrical communication with the first liquid 106. In some embodiments, the insulating element 132 may comprise a hydrophobic surface layer of the second portion 104B of the cavity 104. As described herein, such a hydrophobic surface layer may help to retain the second liquid 108 within the second portion 104B of the cavity 104 (e.g., by an attractive force between the non-polar second liquid and the hydrophobic material) and/or to enable the perimeter of the interface 110 to move along the hydrophobic surface layer (e.g., by electrowetting) to change the shape of the interface.

In order to provide a wide range of focal length, tilt angle, and/or astigmatism variations, a significant difference in optical index between the conductive and non-conductive liquids is beneficial. By replacing the high refractive index, non-polar liquid used in conventional liquid lenses with a low refractive index and low dispersion liquid, a reduction of chromatic aberrations may be achieved, which may provide improved image quality in a camera device comprising a liquid lens in an optical system for auto-focusing and optical image stabilization. The refractive index may be lower than that of the polar liquid, typically >0.08 or above, to produce significant optical power. However, due to the lower refractive index, the interface now provides negative optical power. This negative optical power creates an opportunity for operation that is not suitable for a positive liquid lens. Examples include use as a shutter or reflective display or for imaging virtual objects. A description of these two respective liquids and the respective material properties are provided below.

Conductive liquid

The conductive liquid used to make the negative optical power electrowetting device may be altered to provide a second refractive index that is higher than the refractive index of the non-conductive liquid. In some embodiments, the second refractive index of the conductive liquid is greater than 1.40, greater than 1.42, greater than 1.44, greater than 1.46, greater than 1.48, or greater than 1.50. In some embodiments, the conductive liquid may be formulated and/or selected to have a higher refractive index value than the non-conductive liquid, while the conductive liquid may additionally be adjusted to match other properties of the low refractive index conductive liquid, such as viscosity and temperature. For example, in some embodiments, monopropylene glycol (MPG) and/or ethylene glycol may be adjusted to meet viscosity requirements, while salt additives such as LiBr may be added to increase the refractive index required for the desired application. In some embodiments, the refractive index of the conductive liquid can be increased by adding a water-soluble germanium compound, including, for example, a germanium salt or an organogermanium compound.

In some embodiments, the conductive liquid may be an aqueous solution. In other embodiments, the conductive liquid may not include water. In some embodiments, the conductive liquid may include about 0.01% w/w to about 100% w/w, about 0.1% w/w to about 50% w/w, about 0.1% w/w to about 25% w/w, about 0.1% w/w to about 15% w/w, about 1% w/w to about 10% w/w, or about 1% w/w to about 5% w/w of water, based on the total weight of the conductive liquid. In some embodiments, the conductive liquid may include from about 0.01% w/w to about 100% w/w, from about 1% w/w to about 50% w/w, from about 50% w/w to about 100% w/w, from about 75% w/w to about 95% w/w, or from about 2% w/w to about 25% w/w salt, based on the total weight of the conductive liquid. In some embodiments, the water and/or polar solvent may be mixed with one or more different salts, including organic and/or inorganic salts. The term "ionic salt" as referred to herein refers to salts (such as acetate anions and cations) that are fully or substantially dissociated in water. Also, as referred to herein, the term "ionizable salt" refers to a salt that completely or substantially dissociates in water after chemical, physical, or physicochemical treatment. Examples of anions used in these types of salts include, but are not limited to, halide, sulfate, carbonate, bicarbonate, acetate, 2-fluoroacetate, 2, 2-difluoroacetate, 2,2, 2-trifluoroacetate, 2,2,3,3, 3-pentafluoropropionate, triflate, fluoride, hexafluorophosphate, trifluoromethanesulfonate, and mixtures thereof. Examples of cations used in these types of salts include, but are not limited to, alkali/alkaline earth metal and metal cations, such as sodium, magnesium, potassium, lithium, calcium, zinc, ammonium fluoride (e.g., N- (fluoromethyl) -2-hydroxy-N, N-dimethyl-ethylammonium), and mixtures thereof. In some embodiments, any combination of the above anions and cations can be used in the conductive liquid.

In some embodiments, at least one organic and/or inorganic ionic or ionizable salt is used to impart conductivity to the water and lower the freezing point of the mixed liquor. In some embodiments, ionic salts can include, for example, sodium sulfate, potassium acetate, sodium acetate, zinc bromide, sodium bromide, lithium bromide, and combinations thereof. In other embodiments, the ionic salt may comprise a fluoride salt, including a fluorinated organic ionic salt. In some embodiments, organic and inorganic ionic and ionizable salts can include, but are not limited to, potassium acetate, magnesium chloride, zinc bromide, lithium chloride, calcium chloride, sodium sulfate, sodium triflate, sodium acetate, sodium trifluoroacetate, and the like, and mixtures thereof.

Fluoride salts, including salts of fluorinated organic ions, can advantageously maintain a relatively low refractive index of the conductive liquid while facilitating changes in the physical properties of the conductive liquid, such as lowering the freezing point of the conductive liquid. Unlike traditional chloride salts, fluoride salts may also exhibit reduced corrosion of the materials (e.g., steel, stainless steel, or brass components) that make up the cells of the electrowetting optical device.

The water used in the electrically conductive liquid is preferably as pure as possible, i.e. free or substantially free of any other undesired dissolved components that may alter the optical properties of the electrowetting optical device. In some embodiments, Ultra Pure Water (UPW) having a conductivity of about 0.055 μ S/cm or a resistivity of 18.2MOhm at 25 ℃ is used to form the conductive liquid.

In some embodiments, the conductive liquid may include an antifreeze or freezing point depressant. The use of antifreeze agents such as salts, alcohols, glycols, and/or glycols keeps the conductive liquid in a liquid state at temperatures ranging from about-30 ℃ to about +85 ℃, from about-20 ℃ to about +65 ℃, or from about-10 ℃ to about +65 ℃. In some embodiments, the use of alcohol and/or glycol additives in the conductive and/or non-conductive liquids may help provide a stable interfacial tension between the two liquids over a wide temperature range. Depending on the desired application and properties of the conductive liquid and the resulting liquid lens, the conductive liquid may include less than about 95 wt%, less than about 90 wt%, less than about 80 wt%, less than about 70 wt%, less than about 60 wt%, less than about 50 wt%, less than about 40 wt%, less than about 30 wt%, less than about 20 wt%, less than about 10 wt%, or less than about 5 wt% antifreeze. In some embodiments, the conductive liquid can include greater than about 95 wt%, greater than about 90 wt%, greater than about 80 wt%, greater than about 70 wt%, greater than about 60 wt%, greater than about 50 wt%, greater than about 40 wt%, greater than about 30 wt%, greater than about 20 wt%, greater than about 10 wt%, or greater than about 5 wt% antifreeze. In some embodiments, the antifreeze can be a glycol, including, for example, monopropylene glycol, ethylene glycol, 1, 3-propanediol (trimethylene glycol or TMG), glycerol, dipropylene glycol, and combinations thereof. In some embodiments where a diol is used, the diol may have a weight average molecular weight (Mw) of 200g/mol to 2000g/mol, 200g/mol to 1000g/mol, 350g/mol to 600 g/mol, 350g/mol to 500g/mol, 375g/mol to 500g/mol, or mixtures thereof. In some embodiments, the diol may be a dimer, trimer, tetramer, or any combination of 2 to 100 monomeric diol or triol units (including all integers therebetween).

In some embodiments, the conductive liquid may include at least one viscosity control agent, i.e., a viscosity modifier. The viscosity modifier may comprise any compound or mixture known in the art and may, for example, comprise an alcohol, glycol ether, polyol, polyether polyol, and the like, or mixtures thereof. In some embodiments, the viscosity modifier may include, for example, ethanol, Ethylene Glycol (EG), monopropylene glycol (MPG), 1, 3-propanediol, 1,2, 3-propanetriol (glycerol), and mixtures thereof. In some embodiments, the viscosity modifier has a molecular weight of less than about 130 g/mol. In some embodiments, the same or different alcohols, glycols, and/or diols may be used as antifreeze or viscosity control agents, respectively.

In some embodiments, the conductive liquid may include a biocide to prevent the development of organic elements such as bacteria, fungi, algae, microalgae, and the like, which may degrade the optical properties of the optical electrowetting device, particularly if the lens is driven by electrowetting. The biocide should not change or minimally change the desired optical properties (e.g., transparency and refractive index) of the conductive liquid. The biocide compounds include those known in the art, and may include, for example, 2-methyl-4-isothiazolin-3-one (MIT) and 1, 2-benzisothiazolin-3-one (BIT).

Non-conductive liquid

The refractive index of the non-conducting liquid used to fabricate the negative optical power electrowetting optical devices disclosed herein may be less than 1.40, less than 1.39, less than 1.38, less than 1.37, less than 1.36, less than 1.35, less than 1.34, less than 1.33, less than 1.32, less than 1.31, or less than 1.30. In some embodiments, the non-conductive liquid has a refractive index of less than 1.40. The non-conductive liquid may have a refractive index that is at least 0.06, at least 0.07, at least 0.08, at least 0.09, at least 0.1, at least 0.11, at least 0.12, at least 0.13, at least 0.14, or at least 0.15 less than the second refractive index of the conductive liquid. In some embodiments, the non-conductive liquid has an index of refraction that is at least 0.08 less than the second index of refraction of the conductive liquid. In other embodiments, the non-conductive liquid has a refractive index that is at least 0.1 less than the second refractive index of the conductive liquid. In some embodiments, the non-conductive liquid may have a lower refractive index value than the conductive liquid, while the non-conductive liquid may additionally be adjusted to match other physical properties of the conductive liquid having a higher second refractive index, such as viscosity and density at a given temperature or range of temperatures.

In some embodiments, the non-conductive liquid comprises an alkyl group having 5 to about 40 carbon atoms, a fluorinated alkyl group having 5 to about 40 carbon atoms, a silicone oil, a fluorinated silicone oil, a silane, a fluorinated silane, a perfluoropolyether (PFPE), a siloxane, a fluorinated siloxane, a fluoropolymer, Polytetrafluoroethylene (PTFE), polyvinyl fluoride (PVF), Fluorinated Ethylene Propylene (FEP), Perfluoroalkoxy (PFA), perfluoromethyl vinyl ether, a perfluorinated fluoroelastomer, or a combination thereof. In other embodiments, the non-conductive liquid comprises a linear alkyl group having from 5 to about 20 carbon atoms, a branched alkyl group having from 5 to about 20 carbon atoms, a linear fluorinated alkyl group having from 5 to about 20 carbon atoms, a branched fluorinated alkyl group having from 5 to about 20 carbon atoms, a silicone oil, a fluorinated silicone oil, a silane, a fluorinated silane, a perfluoropolyether (PFPE), a siloxane, a fluorinated siloxane, a fluoropolymer, Polytetrafluoroethylene (PTFE), polyvinyl fluoride (PVF), Fluorinated Ethylene Propylene (FEP), Perfluoroalkoxy (PFA), perfluoromethyl vinyl ether, perfluorinated fluoroelastomers, or combinations thereof.

As used herein, "alkyl" includes both straight and branched chain alkyl groups having from 5 to about 40 carbon atoms, and in some embodiments, from 5 to about 20 carbon atoms, or in other embodiments, from 5 to about 12 carbon atoms. As used herein, "alkyl" may include cycloalkyl as defined below. Alkyl groups may be substituted or unsubstituted. Examples of straight chain alkyl groups include n-pentyl, n-hexyl, n-heptyl, and n-octyl. Examples of branched alkyl groups include, but are not limited to, isopropyl, sec-butyl, tert-butyl, neopentyl, and isopentyl. Representative substituted alkyl groups can be substituted one or more times with, for example, amino, mercapto, hydroxyl, cyano, alkoxy, and/or halo groups (such as F, Cl, Br, and I groups). In some embodiments, the alkyl group may be substituted one or more times with, for example, cyano, alkoxy, and fluoro groups. As used herein, the term haloalkyl is an alkyl having one or more halo groups. In some embodiments, haloalkyl refers to perhaloalkyl.

Cycloalkyl is a cyclic alkyl group such as, but not limited to, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, and cyclooctyl. In some embodiments, cycloalkyl groups have 3 to 8 ring atoms, while in other embodiments the number of ring carbon atoms is 3 to 5, 6, or 7. Cycloalkyl groups may be substituted or unsubstituted. Cycloalkyl groups further include polycyclic cycloalkyl groups such as, but not limited to, norbornyl, adamantyl, bornyl, camphene, isobornene, and carenyl groups; and fused rings such as, but not limited to, naphthylalkyl (decalinyl) and the like. Cycloalkyl also includes rings substituted with straight or branched chain alkyl as defined above. Representative substituted cycloalkyl groups may be mono-substituted or substituted more than once, such as but not limited to: 2, 2-; 2, 3-; 2, 4-; 2, 5-; or a 2, 6-disubstituted cyclohexyl group, or a mono-, di-, or tri-substituted norbornyl or cycloheptyl group, which may be substituted with, for example, alkyl, alkoxy, amino, mercapto, hydroxy, cyano, and/or halogen groups.

In some embodiments, silicone oils and fluorinated silicon-based oils may be used to provide a non-conductive liquid having a refractive index of less than 1.4. Exemplary silicone oils having a refractive index of less than 1.4 include those sold under the trade name

Those sold by Oils 47 (Bluestar Silicones). Both silicone oils and fluorinated silicone oils can be modified in number and weight average molecular weight by controlling the degree of polymerization, thereby changing the viscosity and refractive index. These oils have a basic chemical structure as shown below and are designed according to chain length. In some embodiments, the non-electrically conductive liquid comprises a silicone oil compound having formula (I) and/or a fluorinated silicone oil compound having formula (II):

wherein n is 0 or an integer greater than 0.

In some embodiments, perfluoropolyether compounds can be used to provide non-conductive liquids having refractive indices less than 1.4. Exemplary perfluoropolyether compounds having a refractive index of less than 1.4 include those having the trade name

HT PFPE (Solvay). The perfluoropolyether compounds provide another class of non-conductive liquids having a wide range of viscosity values and densities for matching and blending with other non-conductive liquids,to selectively match the physical properties of the conductive liquid. In some embodiments, the non-electrically conductive liquid comprises a perfluoropolyether compound having the formula (III):

wherein x and y are each integers greater than 0. In some embodiments, x ranges from about 50 to about 500,000, from about 50 to about 50,000, from about 50 to about 5,000, or from about 50 to about 500. In some embodiments, y ranges from about 50 to about 500,000, from about 50 to about 50,000, from about 50 to about 5,000, or from about 50 to about 500.

In some embodiments, fluorinated aliphatic compounds may be used to provide a non-conductive liquid having a refractive index of less than 1.4. Exemplary fluorinated aliphatic compounds having a refractive index of 1.238-1.330 include those sold under the trade name FLUORINERT (manufactured by 3 MTM). The FLUORINERT series includes: FC-87, FC-72, FC-84, FC-77, FC-3255, FC-3283, FC-40, FC-43, FC-70 and FC-5312, wherein the kinematic viscosity (cs) of the series ranges from as low as 0.4cs to as high as 14.0 cs. Fluorinated aliphatic compounds provide another class of non-conductive liquids with a wide range of viscosity values and densities for matching and blending with other non-conductive liquids to selectively match the physical properties of the conductive liquid. Fluorinated aliphatic compounds represent another class of non-conductive liquids suitable for forming the negative lens portion of a liquid lens.

In some embodiments, silanes and silane oligomers, including those under the trade name

Those sold (produced by EVONIK), provide another class of chemicals that may be sufficiently hydrophobic and have a refractive index of less than 1.4. Silanes and silane oligomers provide another class of non-conductive liquids with a wide range of viscosity values and densities for matching and blending with other non-conductive liquids to selectively match the physical properties of the conductive liquid. In some embodiments, the non-electrically conductive liquid comprises a fluorinated silane compound. In some embodimentsThe fluorinated silane compound is trichloro (1H, 2H-perfluorooctyl) silane (FOTS) provided in the following formula (IV). In some embodiments, the non-electrically conductive liquid comprises a fluorinated silane compound having the formula (IV):

the non-conductive liquid disclosed herein may include one or more low refractive index compounds including an alkyl group having 5 to about 40 carbon atoms, a fluorinated alkyl group having 5 to about 40 carbon atoms, a silicone oil, a fluorinated silicone oil, a silane, a fluorinated silane, a perfluoropolyether (PFPE), a siloxane, a fluorinated siloxane, a fluoropolymer, Polytetrafluoroethylene (PTFE), polyvinyl fluoride (PVF), Fluorinated Ethylene Propylene (FEP), Perfluoroalkoxy (PFA), perfluoromethylvinylether, perfluorinated fluoroelastomer, or combinations thereof. The non-conductive liquid may comprise about 50% w/w to about 100% w/w of the low refractive index compound, depending on the desired application and the corresponding properties of the non-conductive liquid. In some embodiments, the non-conductive liquid may include any one or more low refractive index compounds from about 50% w/w to about 100% w/w, from about 50% w/w to about 95% w/w, from 5% w/w to about 95% w/w, or from about 25% w/w to about 75% w/w. In some embodiments, additional non-reactive compounds (e.g., oils, high or low viscosity liquids, oil soluble solids, etc.) may be added separately to the non-conductive liquid to alter the refractive index and electrical properties of the formulated non-conductive liquid.

The non-conductive liquids and corresponding low refractive index compounds disclosed herein may advantageously provide improved performance over a variety of temperature ranges that are advantageous for liquid lens/electrowetting optical devices, particularly those devices used over a wide temperature range. The performance improvements at higher temperatures include temperatures greater than 45 deg.C, greater than 50 deg.C, greater than 55 deg.C, greater than 60 deg.C, greater than 65 deg.C, greater than 70 deg.C, greater than 75 deg.C, and greater than 80 deg.C. The non-conductive liquids and corresponding low refractive index compounds described herein help to improve the transmission recovery time of the liquid lens/electrowetting optical device.

In some embodiments, is notThe conductive liquid may additionally comprise organic or inorganic (mineral) compounds or mixtures thereof. Examples of such organic or inorganic compounds include hydrocarbons, Si-based monomers or oligomers, Ge-based monomers or oligomers, Si-Ge-based monomers or oligomers, high refractive index polyphenylene ether compounds, low refractive index fluorinated or perfluorinated hydrocarbons, or mixtures thereof. In some embodiments, the organic and/or inorganic compound of the non-conductive liquid may include hexamethyldisilazane, diphenyldimethylsilane, chlorophenyltrimethylsilane, phenyltrimethylsilane, phenyltris (trimethylsiloxy) silane, polydimethylsiloxane, tetraphenyltrimethylsiloxane, poly (3,3, 3-trifluoropropylmethylsiloxane), 3,5, 7-triphenylnonamethyl-pentasiloxane, 3, 5-diphenyloctamethyltetrasiloxane, 1,5, 5-tetraphenyl-1, 3,3, 5-tetramethyl-trisiloxane, hexamethylcyclotrisiloxane, hexamethyldigermane, diphenyldimethylgermane, phenyltrimethylgermane. In some embodiments, the organic and/or inorganic compound of the non-conductive liquid may include hexamethyldigermane, diphenyldimethylgermane, hexaethyldigermane, paraffin, or a combination thereof. For example, paraffin oil

P comprises a mixture of hydrocarbons produced by Exxon Mobil and commercially available.

It has been found that the low refractive index non-conductive liquids (oils) for negative optical power liquid lens/electrowetting optical applications disclosed herein are capable of providing a wide range of focal length, tilt angle and/or astigmatism changes. To achieve these benefits, the non-conductive liquid should meet at least one or more of the following properties: 1) a significantly lower refractive index compared to the conductive liquid; 2) a density matching or similar to the conductive liquid over the operating temperature range of the liquid lens; 3) low miscibility with conductive liquids in the operating temperature range of the liquid lens; 4) chemical stability with respect to each component of the non-conductive liquid and the nucleophilic aqueous-based electrolyte (conductive liquid); 5) Sufficient viscosity to match or achieve the desired response time of the liquid lens. Using the materials as disclosed herein, a new combination of liquid materials for use in non-conductive liquids/fluids can be achieved that meets each of the five criteria described above while being able to maintain these properties in a liquid lens/electrowetting optical device over a wide temperature range in static and/or varying environments.

In view of the above criteria, the non-conductive liquid and the conductive liquid used in the negative optical power electrowetting optical device are designed to be immiscible when they are combined together, and the liquids are formulated to closely match the viscosity and density of each other. The viscosity of each liquid can also be carefully matched, particularly in terms of temperature range. In addition, the refractive index may vary as a function of wavelength, and close matching to this property may also be considered herein. In some embodiments, the combination of non-conductive and conductive liquids may reduce the inherent visible light absorption. Thus, a range of different liquid systems, compositions or mixtures as defined herein may be utilized to meet the requirements listed above, with particular attention being paid to the fact that the non-conductive liquid has a refractive index which is less than the second refractive index of the conductive liquid. In some embodiments, the non-conducting liquid is oil and the conducting polar liquid is an antifreeze liquid containing salts, typically water. In some embodiments, the non-conductive liquid may contain fluorine atoms in order to have a low refractive index of less than 1.4 for the non-conductive liquid component (the material portion of the lens used to modify the incident beam to achieve the desired focus). In some embodiments, the difference between the refractive indices of the non-conductive liquid and the conductive liquid is about 0.1. In some embodiments, the conductive liquid may be doped with a salt to improve its conductivity, while in other embodiments, the salt may act as a freezing point depressant, making the salt serve a dual purpose.

With respect to refractive index parameters, in some embodiments, the non-conductive liquid may have a refractive index of less than 1.40, less than 1.39, less than 1.38, less than 1.37, less than 1.36, less than 1.35, less than 1.34, less than 1.33, less than 1.32, less than 1.31, or less than 1.30. in other embodiments, the non-conductive liquid may have a refractive index of about 1.40, about 1.39, about 1.38, about 1.37, about 1.36, about 1.35, about 1.34, about 1.33, about 1.32, about 1.31, or about 1.30. in some embodiments, the difference in refractive index between the conductive liquid and the non-conductive liquid (Δ η) may be about 0.04 to about 0.2 or about 0.08 to about 0.15. the range of optical indices of the optical applications may include features such as pitch, tilt, astigmatism compensation, and the desired refractive index difference between the conductive liquid and the variable focus liquid, wherein the optical application may include a more than 0.08, more than 0.15, more than 10, more than the optical axis of the variable focus device, or the optical device, wherein the optical device may be suitable for example, or the optical device, and/or the optical device, for example, for a variable focus device, for example, a variable focus device, for example, a zoom device, and/or a device.

With respect to the density parameter, substantially matching the density of the non-conductive liquid to the density of the conductive liquid may help provide a multifunctional liquid lens/electrowetting optical device having a wide range of focal lengths at various tilt angles. In some embodiments, the density difference (Δ ρ) between the non-conductive liquid and the conductive liquid may be less than 0.1g/cm over a wide temperature range including about-30 ℃ to about 85 ℃ or about-20 ℃ to about 65 ℃³Less than 0.01g/cm³Or less than 3.10^-3g/cm³。

With respect to miscibility parameters, the disclosed conductive and non-conductive liquids are considered immiscible. In some embodiments, the partial miscibility of the conductive liquid and the non-conductive liquid can be less than 2%, less than 1%, less than 0.5%, or less than 0.2%, where each of these values can be measured over a wide temperature range, including for example-30 ℃ to 85 ℃, or-20 ℃ to 65 ℃.

With respect to stability parameters, the non-conducting liquid remains in a liquid state at a temperature in the range of about-10 ℃ to about +65 ℃, about-20 ℃ to about +65 ℃, or about-30 ℃ to about +85 ℃. In addition, the non-conducting liquid may not show any detectable signs of reaction or decomposition with the nucleophilic aqueous-based electrolyte used in the conducting liquid. Finally, the respective components of the respective conductive and non-conductive liquids are also chemically stable with respect to each other, i.e. they have no or substantially no chemical reaction in the presence of other compounds of the conductive and non-conductive liquids within the functional temperature range of the device.

With respect to viscosity parameters, a low viscosity non-conductive liquid may be desirable in some applications because a lower viscosity liquid is expected to be able to respond to a varying voltage applied through the cell of the liquid lens/electrowetting optical device. The water-based conductive layer is generally low in viscosity and responds quickly to voltage changes. In some embodiments, the viscosity of the non-conductive liquid may be less than 40cs, less than 20cs, or less than 10cs, as measured at all temperatures in the range of-20 ℃ and +70 ℃.

In some embodiments, a non-conductive liquid with a refractive index of 1.2909 and an abbe number of 101.3 at 546nm may be coupled with a conductive liquid with a second refractive index of 1.3887 and an abbe number of 58.568 to form a negative liquid lens or a negative optical power electrowetting device. By applying a negative voltage on the four electrodes to the negative optical power electrowetting device, the liquid interface between the non-conductive liquid and the conductive liquid can be altered to produce a negative curvature of +10 diopters (positive optical power) or a voltage can be applied to produce a positive curvature of up to at least-30 diopters (negative optical power). In some embodiments, the negative optical power electrowetting device can produce a positive curvature (negative optical power) of at least-10 diopters, at least-20 diopters, at least-30 diopters, at least-40 diopters, or at least-50 diopters.

Referring now to fig. 2, a schematic cross-sectional view of a conventional liquid lens 100 providing positive optical power is shown. The conventional liquid lens 100 includes a first liquid 106 (e.g., a polar liquid) and a second liquid 108 (e.g., an oil or a non-polar liquid) between a top window 114 and a bottom window 116. When light is directed through the top window 114 and projected through the first liquid 106, the second liquid 108, and the corresponding interface 110 (see fig. 1) of the liquid lens 100, the liquid lens 100 generates positive optical power by an increase in voltage because the refractive index of the second liquid 108 is greater than the second refractive index of the first liquid 106. Thus, as shown, light passing through the liquid lens 100 is focused as it passes through the interface 110 between the first liquid 106 and the second liquid 108.

Referring now to fig. 3, a schematic cross-sectional view of a liquid lens 100 providing a tilted interface is shown, according to some embodiments of the present disclosure. Similar to the structure provided in fig. 2, liquid lens 100 includes a first liquid 106 (e.g., a polar liquid) and a second liquid 108 (e.g., an oil or a non-polar liquid) between a top window 114 and a bottom window 116. Fig. 3 shows an embodiment where the liquid lens 100 is moved upward and a voltage is applied to tilt the liquid interface 110 (see fig. 1) to compensate for the green light and center the image. Due to the dispersion, the blue light 140 is not fully compensated and leaves at a slightly positive angle with respect to the green light. In addition, the red light 144 is also not fully compensated and exits at a slightly negative angle relative to the green light due to chromatic dispersion. In summary, when light is directed through the top window 114 and projected through the first liquid 106, the second liquid 108, and the respective interfaces 110 of the liquid lens 100, green light and the center image are adjusted as shown, but blue light 140 and red light 144 are both dispersed.

Fig. 4 is a schematic cross-sectional view illustrating a liquid lens providing negative optical power according to some embodiments of the present disclosure. Similar to the structure provided in fig. 2, liquid lens 100 includes a first liquid 106 (e.g., a polar liquid) and a second liquid 108 (e.g., an oil or a non-polar liquid) between a top window 114 and a bottom window 116. When light is directed through the top window 114 and projected through the first liquid 106, the second liquid 108, and the corresponding interface 110 (see fig. 1) of the liquid lens 100, the liquid lens 100 generates negative optical power by an increase in voltage because the refractive index of the non-conductive liquid is less than the second refractive index of the conductive liquid. Thus, as shown, light passing through the liquid lens 100 is defocused as it passes through the interface 110 between the first liquid 106 and the second liquid 108.

Fig. 5 is a graph of chromatic aberration for positive and negative optical power liquid lenses according to some embodiments of the present disclosure. The difference in image height separation between blue and green light of a conventional liquid (conventional liquid lens) (solid line position with positive value) and a liquid of the invention (liquid lens of the invention) (marked by a dotted line with positive value) is used to illustrate chromatic aberration. Furthermore, the difference in image height separation between red and green light is also reduced when using the liquid of the present invention. This reduced image height separation between wavelengths improves (height decreases) by about 50% when optical image stabilization is applied, by using a low refractive index non-conductive liquid. The reduced color difference may reduce image blur and improve image quality.

Fig. 6A-6C are schematic cross-sectional views of a liquid shutter according to some embodiments of the present disclosure. The liquid shutter comprises a negative optical power electrowetting optical device 100, the negative optical power electrowetting optical device 100 having: a non-conductive liquid having a refractive index; a conductive liquid having a second refractive index; and a dielectric surface in contact with both the conductive liquid and the non-conductive liquid. The liquid shutter further comprises an objective lens 148, an imaging lens 156, and a blocking member 152 located between the negative optical power electrowetting optical device 100 and the imaging lens 156. The non-conductive liquid has a refractive index less than the second refractive index of the conductive liquid, and the conductive liquid is immiscible with the non-conductive liquid. Referring to fig. 6A, when no voltage is applied to the liquid lens 100, the liquid shutter is activated, and light is blocked by the blocking member 152. For example, light blocked by the blocking member 152 may be prevented from being incident on the imaging lens 156, and the imaging lens 156 refocuses the light to project the image 160 on a sensor or other light receiving member. Referring to fig. 6B, the liquid shutter is deactivated and light is defocused and refracted with the negative optical power electrowetting optical device 100 to bypass the blocking member 152 and impinge on the imaging lens 156, which refocuses the light to impinge the image 160 on a sensor or other light receiving member. Referring to fig. 6C, the image of the activated shutter (fig. 6A) and the image of the deactivated shutter (fig. 6B) are superimposed to emphasize two illumination configurations, demonstrating the use of the blocking member 152 in conjunction with the imaging lens 156.

Still referring to fig. 6A-6C, because both the conductive liquid and the non-conductive liquid in the liquid lens 100 have relatively low refractive indices and low dispersion, the introduced chromatic aberration is significantly improved compared to conventional liquid lenses using higher index oils. This aspect is particularly important for applications where liquid lens 100 is used for optical image stabilization, since it significantly reduces aberrations introduced during stabilization. Since the non-conductive liquid used in these embodiments has a lower refractive index than the second refractive index of the conductive liquid, the liquid lens 100 operates with negative optical power when a voltage is applied. Negative optical power electrowetting optics enable new applications that require focusing beyond infinity (virtual object). If the negative optical power electrowetting optical device is capable of focusing on an infinite object when a voltage is applied (negative optical power configuration), the negative optical power electrowetting optical device is capable of focusing at a shorter object distance by lowering the voltage of the liquid lens, thereby operating as an autofocus element. The negative optical power liquid lens 100 can also operate as a high efficiency liquid shutter if coupled with secondary optics such as the objective lens 148 and the imaging lens 156 shown in fig. 6A-6C. Such high efficiency liquid shutters are of particular value because they have no mechanical parts, which makes the shutters have a long life. Furthermore, the switching rate of these liquid shutters can be in milliseconds or very fast. In some embodiments, the liquid shutter has a switching time of less than 25 milliseconds, less than 20 milliseconds, less than 15 milliseconds, less than 10 milliseconds, or less than 5 milliseconds. The design of the negative optical power electrowetting optics may require a minimum current and corresponding power to drive the negative power electrowetting optics; thus, during the lifetime of the electrowetting optical device, the power consumption may be relatively low.

According to some embodiments, the electrowetting optical device comprises a voltage source for applying an alternating voltage to change a meniscus formed between the conducting liquid and the non-conducting liquid to control the focal length of the lens. In some embodiments, the electrowetting optical device further comprises a driver or similar electronics for controlling the lens, wherein the lens is integrated with the driver or similar electronics in the liquid lens. In other embodiments, the electrowetting optical device may comprise a plurality of lenses in combination with at least one actuator or similar electronic device.

Electrowetting optical devices may be used as or as part of variable focus liquid lenses, optical zoom, ophthalmic devices, devices with variable optical axis tilt, image stabilization devices, beam deflection devices, variable illumination devices, and any other optical device using electrowetting. In some embodiments, the liquid lens/electrowetting optical device may be incorporated or installed in any one or more devices, including, for example, a camera lens, a cell phone display, an endoscope, a telemeter, a dental camera, a bar code reader, a beam deflector, and/or a microscope.

In some embodiments, a negative power electrowetting optical device may be used for a front-facing camera. In front camera applications using negative power electrowetting optics, a low optical power configuration may be used for close distances (arm distances), while higher negative optical power may be needed at longer distances, such as at self-timer stick distances. Using a negative power electrowetting optical device a power configuration using low optical power at a short distance and higher optical power at a longer distance can be obtained. Furthermore, such negative power electrowetting optics may achieve reduced or reduced chromatic aberration. In other embodiments, negative power electrowetting optical devices may be used for switching applications including, but not limited to, optical fiber communications, electro-optical switching or switching, optical logic memory, optical interconnects, sensors, optical waveguide and waveguide array interfaces, embedded optical interfaces, and the like.

Examples

The following table provides various non-conductive liquids having various ranges of viscosity, density, and refractive index. In some embodiments, the non-electrically conductive liquids may be mixed and blended together to meet the specifications and desired characteristics of the negative optical power electrowetting device. As is currently known and practiced, none of these non-conductive liquid components are or will be used in positive optical power liquid lens designs due to their low refractive index. Although some compounds such as acetonitrile may be selected to provide a low refractive index of 1.3405, various other important physical properties, such as miscibility, viscosity, and density, must be balanced to provide a functional negative optical power electrowetting device. In embodiments disclosed herein, the non-conductive liquid (oil) of the negative optical power electrowetting device may be sufficiently hydrophobic to be separated from the conductive liquid while maintaining a refractive index below 1.40. Examples of non-conductive liquids that may be used alone or in any combination as described herein are provided in table 1.

TABLE 1

Referring now to fig. 7A-7B, there are shown schematic cross-sectional views of a liquid lens 100 located in a cell phone camera module. Referring to fig. 7A, the liquid lens 100 and corresponding optics are designed such that an object at infinity is focused when a driving voltage is applied to the liquid lens 100, in the liquid lens 100 the non-conductive liquid has a refractive index less than the second refractive index of the conductive liquid and wherein the conductive liquid is immiscible with the non-conductive liquid. Similar to the previously provided structure, the liquid lens 100 includes a first liquid 106 (e.g., a polar liquid) and a second liquid 108 (e.g., an oil or a non-polar liquid) between a top window 114 and a bottom window 116. When light is directed through the top window 114 and projected through the first and

second liquids

106, 108 of the liquid lens 100 and the corresponding interface 110, the liquid lens 100 generates negative optical power by an increase in voltage because the refractive index of the non-conductive liquid is less than the second refractive index of the conductive liquid. In some embodiments, the liquid lens 100 may be included in a camera module described in fig. 7A and 7B, and the liquid lens 100 or negative optical power electrowetting optics may be modified as described herein.

Still referring to fig. 7A-7B, the optics surrounding negative power liquid lens 100 include a first fixed optical lens 164, a second fixed optical lens 168, a third fixed optical lens 172, a fourth fixed optical lens 176, a fifth fixed optical lens 180, a sixth fixed optical lens 184, a spectral filter 188, and a camera sensor 192. The liquid lens 100 includes a first liquid 106 and a second liquid 108 positioned between a top window 114 and a bottom window 116. Referring to fig. 7B, the structure and corresponding optics of the liquid lens 100 located in the cell phone camera module are the same as described in fig. 7. In fig. 7B, the voltage of the liquid lens 100 is lowered to achieve auto-focusing for an object less than infinity in distance (such as an object located at 10 cm).

Still referring to fig. 7A-7B, the description of the optical design for simulated use of a negative optical power electrowetting device located inside a camera module optical system having an 80 ° field of view and an aperture of F/1.9 is summarized in table 2 provided below:

TABLE 2

Number of surfaces	Radius of	Thickness of	Refractive index of glass
				Object	Infinite number of elements	Infinite number of elements
1:	3.05089	0.327851	1.546
				2:	87.08640	0.023537
Stop	Infinite number of elements	0.000000
				4:	Infinite number of elements	0.125000	1.525
5:	Infinite number of elements	0.230000	1.2909:101.3
				6:	-12.00000	0.150000	1.389:58.57
7:	Infinite number of elements	0.100000	1.525
				8:	Infinite number of elements	0.02000
9:	2.87655	0.346054	1.546
				10:	2.27905	0.132495
11:	-4.37484	0.695409	1.546
				12:	-3.72145	0.291455
13:	-1.26028	0.302801	1.649
				14:	-3.40920	0.100000
15:	2.70936	0.934360	1.546
				16:	-1.79567	0.487366
17:	-2.98395	0.300000	1.546
				18:	0.89690	0.456602
19:	Infinite number of elements	0.210000	1.519
				20:	Infinite number of elements	0.150000
IMG:	Infinite number of elements	-0.038492

The Fobbs polynomial descriptions of surfaces 1-2 and surfaces 9-18 defined by the respective surfaces of the camera module, first fixed optical lens 164, second fixed optical lens 168, third fixed optical lens 172, fourth fixed optical lens 176, fifth fixed optical lens 180, sixth fixed optical lens 184, and spectral filter 188 are provided in tables 3-14 below, respectively:

TABLE 3

TABLE 4

TABLE 5

TABLE 6

TABLE 7

TABLE 8

TABLE 9

Watch 10

TABLE 11

TABLE 12

Watch 13

TABLE 14

While exemplary embodiments and examples have been set forth for the purpose of illustration, the foregoing description is not intended to limit the scope of the disclosure and the appended claims in any way. Thus, variations and modifications may be made to the above-described embodiments and examples without departing substantially from the spirit and various principles of the disclosure. All such modifications and variations are intended to be included herein within the scope of this disclosure and protected by the following claims.

Claims

1. A negative optical power electrowetting optical device comprising:

a non-conductive liquid having a refractive index;

a conductive liquid having a second refractive index; and

a dielectric surface in contact with both the conductive liquid and the non-conductive liquid,

wherein the non-conductive liquid has a refractive index less than the second refractive index of the conductive liquid, and wherein an interface between the conductive liquid and the non-conductive liquid forms a lens.

2. The electrowetting optical device according to claim 1, wherein the non-electrically conductive liquid comprises a silicone oil compound having formula (I) and/or a fluorinated silicone oil compound having formula (II):

wherein n is 0 or an integer greater than 0.

3. The electrowetting optical device of claim 1, wherein the non-electrically conductive liquid comprises a perfluoropolyether compound having a formula (III):

wherein x and y are each integers greater than 0.

4. The electrowetting optical device of claim 1, wherein the non-electrically conductive liquid comprises a fluorinated silane compound having the formula (IV):

5. electrowetting optical device according to any of claims 1-4, wherein the non-conductive liquid has a refractive index of less than 1.40.

6. Electrowetting optical device according to any of claims 1-4, wherein the non-conductive liquid has a refractive index which is at least 0.08 less than the second refractive index of the conductive liquid.

7. Electrowetting optical device according to any one of claims 1-4, wherein the non-conductive liquid has a density of 1.00g/cm at 20 ℃³To 1.10g/cm³。

8. The electrowetting optical device according to any one of claims 1-4, wherein the non-conductive liquid has a viscosity at 20 ℃ of about 2cs to about 10 cs.

9. A camera module comprising an electrowetting optical device according to any one of claims 1-4.

10. A liquid shutter, comprising:

a negative optical power electrowetting optical device comprising:

a non-conductive liquid having a refractive index;

a conductive liquid having a second refractive index; and

a dielectric surface in contact with both the conductive liquid and the non-conductive liquid;

an imaging lens; and

a blocking member located between the negative optical power electrowetting optical device and the imaging lens,

11. The liquid shutter according to claim 10, wherein the liquid shutter has a switching time of less than 10 milliseconds.

12. The liquid shutter according to any of claims 10-11, wherein the non-conductive liquid has a refractive index of less than 1.40.

13. The liquid shutter according to any of claims 10-11, wherein the non-conductive liquid has an index of refraction that is at least 0.08 less than the second index of refraction of the conductive liquid.

14. A negative optical power liquid system comprising:

a non-conductive liquid having a refractive index; and

a conductive liquid having a second refractive index,

wherein the non-conductive liquid has a refractive index less than the second refractive index of the conductive liquid, and wherein the conductive liquid is immiscible with the non-conductive liquid.

15. The negative optical power liquid system of claim 14, wherein the non-electrically conductive liquid comprises a perfluoropolyether compound having the formula (II):

wherein x and y are each integers greater than 0.

16. The negative optical power liquid system of any one of claims 14-15, wherein the non-conductive liquid has a refractive index of less than 1.40.

17. The negative optical power liquid system of any of claims 14-15, wherein the non-conductive liquid has an index of refraction that is at least 0.08 less than the second index of refraction of the conductive liquid.